(a) Field of the Invention
The present invention relates to an air-purifying apparatus for collecting dust particles and the like floating in the air, and particularly to an air-purifying apparatus of the electrostatic fiber-layer dust filter type, wherein a fiber-layer filter formed by a dielectric material is clamped between electrode plates with high voltage applied thereto, dielectric polarization is thereby generated in the fiber-layer filter so as to absorb dust particles.
(b) Description of the Prior Art
Various techiques have been devised as techniques for collecting dust particles floating in the air. For instance, there is a method whereby dust particles is collected by catching the dust particles by filter means such as a net, fibers, and activated charcoal used for ventilating and air-conditioning equipment (refer to U.S. Pat. Nos. 3,828,530, 3,902,877, 4,272,261, etc.); However, it has not been possible to collect such fine particles as smoke. As a method for improving this point, a method was devised whereby dust particles are absorbed forcibly. As one example, there is a method of collecting dust particles electrostatically, which is widely adopted as an air cleaner for vehicles in recent years (for instance, refer to U.S. Pat. No. 3,108,865). This is a method whereby dust particles contained in the sucked air is charged with electricity by means of a corona discharge, and then the electrified dust particles are collected by a porous metal filter. According to this method, a conductor has been used as a filter, and a foamed metal has been used since it is necessary to make the filter thick. However, although dust particles adhered to the inner fine pores of the foamed metal can be removed to some extent by cleaning, it is not possible to clean them completely. Furthermore, although the life of the filter is long, the filter has been inconvenient to use. In addition, there is an air-purifying apparatus using electret fiber-layer filter. This air-purifying apparatus does not require a high-voltage device since the filter maintains electric polarization, but it is not possible to reuse it by cleaning it.
As a method of collecting dust for obviating the drawbacks of the aforementioned dust collecting methods, there is a method using an electrostatic fiber-layer dust-collecting filter, disclosed in the Japanese utility Model Publication No. 26039/1972 and the Japanese Patent Publication No. 41709/1976. In this method, a fiber-layer filter formed by a dielectric material is clamped between electrode plates with a high voltage applied thereto to generate dielectric polarization in the fiber-layer filter, thereby absorbing dust particles. This method has advantages in that the filter can be washed by a washing machine or the like and can be used repeatedly, and, at the same time, a reduction in the dust-collecting performance is small since a high voltage is applied even if dust particles are adhered to it.
In an air-purifying apparatus using the electrostatic fiber-layer dust-collecting filter system, the construction is such that a filter is provided midway in the air channel, so that it is necessary to provide a door for removing the filter, and it has been necessary to disassemble the air-purifying apparatus when conducting maintainance and inspection. This has also been true with the case of the U.S. Pat. No. 4,272,261, which was earlier cited as an example using a filter consisting of a net, fibers, etc.
In the case of the U.S. Pat. No. 3,828,530, however, the main filter is provided not midway in the air channel but along the outlet port. However, the filter is secured to the body, with the result that it has not been possible to easily effect the removal of the body and hence its maintenance and inspection.